Partial aortic occlusion devices and methods for cerebral perfusion augmentation

Abstract

Methods are provided for partial aortic occlusion for cerebral perfusion augmentation in patients suffering from global or focal cerebral ischemia. Alternatively, the methods can be used to partially occlude aortic blood flow to condition the spinal cord to secrete neuroprotective agents prior to abdominal aortic aneurysm repair. The methods can also be used to partially occlude the renal arteries to reduce renin secretion in hypertensive patients. Partial occlusion of a vessel can be accomplished by a device comprising an elongate catheter, a distally mounted expandable occluder, a variable flow mechanism, and a manometer. The occluder may comprise two conical shells or an inflatable ring-shaped balloon disposed about a cylindrical sleeve. Other medical devices, such as an atherectomy catheter, can be inserted distal the occluder to provide therapeutic intervention.

What is claimed is:  
     
       1. A method for increasing cerebral blood flow, comprising the steps of: 
       advancing a catheter into the descending aorta, the catheter having a proximal region, a distal region, and an expandable member mounted on the distal region;  
       locating the expandable member downstream from the takeoff of the bracbiocephalic artery;  
       expanding the expandable member to at least partially obstruct blood flow in the aorta during systole and diastole;  
       measuring a physiologic parameter; and  
       adjusting the expansion of the expandable member based on the measured physiologic parameter.  
     
     
       2. The method of  claim 1 , wherein the physiologic parameter is blood pressure. 
     
     
       3. The method of  claim 1 , wherein the physiologic parameter is cerebral blood flow. 
     
     
       4. The method of  claim 1 , wherein the expandable member is a balloon. 
     
     
       5. The method of  claim 1 , wherein the step of expanding the expandable member includes maintaining the expandable member in an expanded condition during systole and diastole. 
     
     
       6. The method of  claim 1 , wherein blood flow to the cerebral vasculature increases by at least 20%. 
     
     
       7. The method of  claim 1 , wherein the catheter is first inserted into a peripheral artery, and then advanced into the descending aorta. 
     
     
       8. A method for increasing blood flow to a patient's cerebral vasculature, comprising the steps of: 
       providing a catheter having a proximal end, a distal end, and an expandable constrictor mounted on the distal end, and a lumen extending from the proximal end and communicating with a port distal the constrictor;  
       advancing the distal end of the catheter into the descending aorta;  
       locating the constrictor downstream from the takeoff of the brachiocephalic artery;  
       expanding the constrictor to at least partially occlude blood flow in the aorta during systole and diastole, wherein blood pressure in the proximal aorta increases and blood pressure in the distal aorta decreases; and  
       advancing a medical instrument through the lumen, beyond the distal port, and into an artery which branches from the aorta.  
     
     
       9. The method of  claim 8 , wherein the step of expanding the constrictor includes maintaining the expanded constrictor during systole. 
     
     
       10. The method of  claim 8 , wherein the medical instrument is selected from the group consisting of a guiding catheter, an infusion catheter, an angioplasty catheter, a laser catheter, an angiography catheter, a therapeutic ultrasound catheter, a hypothermia catheter, a stent catheter, an imaging catheter, a perfusion catheter, an atherectomy catheter, an occlusion catheter, an EP catheter, and an aspiration catheter. 
     
     
       11. The method of  claim 8 , wherein the medical instrument is an interventional instrument. 
     
     
       12. The method of  claim 11 , wherein the interventional instrument is selected from the group consisting of an infusion catheter, an angioplasty catheter, a laser catheter, an angiography catheter, a therapeutic ultrasound catheter, a hypothermia catheter, a stent catheter, an imaging catheter, a perfusion catheter, an atherectomy catheter, an occlusion catheter, an EP catheter, and an aspiration catheter. 
     
     
       13. A method for increasing blood flow to a patient's cerebral vasculature, comprising the steps of: 
       providing a catheter having a proximal end, a distal end, and an expandable constrictor mounted on the distal end;  
       inserting the distal end of the catheter into the descending aorta;  
       locating the constrictor downstream from the takeoff of the brachiocephalic artery; and  
       expanding the constrictor to partially occlude blood flow in the aorta and maintaining the expanded constrictor during systole, wherein blood pressure in the proximal aorta increases and blood pressure in the distal aorta decreases, and wherein blood flow to the cerebral vasculature increases and exaggerates the pulse wave to enhance the pulsatile wave form.  
     
     
       14. The method of  claim 13 , further comprising the steps of: 
       measuring a first blood pressure at a location distal the constrictor; and  
       adjusting the constrictor based on the first measured blood pressure.  
     
     
       15. The method of  claim 14 , further comprising the step of measuring a second blood pressure at a location proximal the constrictor, and wherein the constrictor is adjusted based on a comparison of the first and second measured blood pressures. 
     
     
       16. The method of  claim 13 , wherein the constrictor comprises a balloon having proximal and distal ends separated by a length of no more than 20 cm. 
     
     
       17. A method for increasing blood flow to a patient's cerebral vasculature, comprising the steps of: 
       providing a catheter having a proximal end, a distal end, and an expandable constrictor mounted on the distal end;  
       advancing the distal end of the catheter into the descending aorta;  
       locating the constrictor downstream from the takeoff of the brachiocepliac artery;  
       expanding the constrictor to at least partially occlude blood flow in the aorta during systole and diastole, wherein blood pressure in the proximal aorta increases and blood pressure in the distal aorta decreases;  
       measuring a first blood pressure at a location proximal the constrictor and measuring a second blood pressure at a location distal the constrictor; and  
       adjusting the constrictor based on a comparison of the first and second measured blood pressures.  
     
     
       18. The method of  claim 17 , wherein the step of expanding the constrictor includes maintaining the expanded constrictor during systole. 
     
     
       19. A method for increasing blood flow to a patient's cerebral vasculature, comprising the steps of: 
       providing a catheter having a proximal end, a distal end, and an expandable constrictor mounted on the distal end;  
       inserting the distal end of the catheter into the descending aorta;  
       locating the constrictor downstream from the takeoff of the brachiocephalic artery; and  
       expanding the constrictor to partially occlude blood flow in the aorta and maintaining the expanded constrictor during systole, wherein blood pressure in the proximal aorta increases and blood pressure in the distal aorta decreases, and wherein blood flow to the cerebral vasculature increases.  
     
     
       20. The method of  claim 19 , wherein the partial occlusion of aortic blood flow is continuous. 
     
     
       21. The method of  claim 19 , wherein aortic blood flow is partially occluded downstream from the takeoff of the left subclavian artery or the brachiocephalic artery. 
     
     
       22. The method of  claim 19 , wherein aortic blood flow is partially occluded upstream from the takeoff of the left subclavian artery. 
     
     
       23. The method of  claim 19 , wherein the patient suffers from global cerebral ischemia and blood flow to the cerebral vasculature is increased. 
     
     
       24. The method of  claim 19 , wherein the patient suffers from focal cerebral ischemia or asymptomatic vasospasm and blood flow to the cerebral vasculature is increased. 
     
     
       25. The method of  claim 19 , further comprising the step of inserting the distal end of the catheter through an incision on a peripheral artery. 
     
     
       26. The method of  claim 25 , wherein the peripheral artery is the femoral artery. 
     
     
       27. The method of  claim 25 , wherein the peripheral artery is the subclavian artery. 
     
     
       28. The method of  claim 19 , wherein blood flow through the partial occlusion is varied. 
     
     
       29. The method of  claim 19 , wherein at least one of the blood pressure upstream and downstream from the partial occlusion is measured, and wherein blood flow at the partial occlusion is varied based on the blood pressure measurement. 
     
     
       30. The method of  claim 19 , further comprising the step of removing a thromboembolic material from the carotid artery. 
     
     
       31. The method of  claim 19 , further comprising the step of localizing the constrictor with transesophageal echocardiography. 
     
     
       32. The method of  claim 19 , further comprising the step of localizing the constrictor with angiogram. 
     
     
       33. The method of  claim 19 , wherein the distal end of the catheter is inserted into the descending aorta in a antegrade direction. 
     
     
       34. The method of  claim 19 , wherein the constrictor is located in the aorta upstream from the renal arteries. 
     
     
       35. The method of  claim 19 , wherein blood flow to the cerebral vasculature increases by at least 20% and exaggerates the pulse wave to enhance the pulsatile wave form.